The MAX17553 is an ultra-small, high-efficiency, high voltage, synchronous step-down DC-DC converter with integrated MOSFETs that operates over a wide input voltage range from 4V to 60V and delivers up to 50mA of load current. The MAX17553 is available in three variants: MAX17553A, MAX17553B, and MAX17553C. MAX17553A and MAX17553B are fixed 3.3V and 5V output voltage devices, respectively. MAX17553C is an adjustable output (0.8V to 0.9 x VIN) device. The feedback-voltage regulation accuracy of the converters over the -40°C to +125°C temperature range is ±1.5% for MAX17553A and MAX17553B, and ±1.25% for MAX17553C.
The device features a peak-current-mode control architecture. During normal operation, at each rising edge of the clock, the high-side p-MOSFET turns on and remains on until either the appropriate or maximum duty cycle is reached, or the peak current limit is detected. During the high-side p-MOSFET on-time, the inductor current ramps up. During the rest of the switching cycle or until the inductor current reaches zero, the high-side p-MOSFET remains off and the low-side n-MOSFET remains on, and the inductor current ramps down. The device features the Discontinuous Conduction Mode (DCM), in which the negative inductor current is inhibited to enable higher light load efficiency. In DCM, the device operates at a fixed switching frequency until the minimum on-time is reached. If the load demand is less than the energy corresponding to the minimum on-time pulse, the converter skips pulses to maintain output voltage regulation.
A fixed soft-start time of 3.2ms (typ) allows users to reduce input inrush current. An open-drain active-low RESET feature provides a power-good signal to the system upon achieving successful regulation of the output voltage.
Applications
- Factory Automation
- Aftermarket Market Automotive
- General Point of Load
